1. Field of the Invention
The present invention relates to a signal processor for processing signals read from an information recording medium such as a CD (Compact Disk), DVD (Digital Versatile Disk), and MD (Mini Disk).
2. Description of the Related Art
There has been developed a digital playback system capable of audio effects control in real time through tempo (BPM: Beats Per Minute) change applied to playback audio of audio data read from an information recording medium such as CD. Such a digital playback system allows users' real-time processing so as to playback audio through operation of dials and buttons, e.g., tempo acceleration, tempo deceleration, playback pause, and backward playback. With such processing, original audio effects can be extemporaneously produced by the user. Conventionally, with an analog record player, tempo change of playback audio has been done by varying the movement speed of a phonograph needle that traces grooves formed on an analog record for audio recording. This is done by users during playback of the analog record by forcibly rotating a turntable carrying thereon the analog record with a speed different from the normal rotation speed. Such tempo change and others conventionally done with the analog record player is now done by the above-described digital playback system using CDs and DVDs which store digital information.
The conventional technology relevant to such a digital playback system is found in Patent Document 1 (Japanese Patent Kokai No. 2003-132634), for example. While, in recent years, optical disks storing video information such as movies have been commonly on the market, no system is yet available for exercising real-time control over video effects during video playback from such optical disks.